The big deal about Halloween is its history.
From my limited knowledge, it started out hundreds of years ago as Hallow's Eve. Hallow's Eve was a night when spirits might come and bring bad luck to a household, so people burned candles by their door, so the light would keep the spirits - dark, of course - away. The candle has evolved into the Jack-o-lantern, and spirits to ghost costumes. The reason the Jack-o-lantern has its unusual name is that there was a man named Jack, acording to legend, who carried a lantern. I don't remember the exact story, but everyone was afraid of him.
So that's why Halloween is seen as a scary day. Feelings last longer than rituals.
(My history may be off a little, because I heard it a few years ago. I think I got the basic idea, but if I messed up the details, please correct me.)
I don't care if you're an old fart, because old people are smarter than me.
-Me. (reply in the Alley)